By substitution;
E = ħ22k2/2m
λ = h/p (de broglie wavelength)
p = mv
h = λmv
so k = 2π√(2Em) / λmv
??
apparently I should get;
k=2π/λ
What I have is a multiple of 2π/λ
What have I done wrong / what else should I do
Thanks in advance for and help you offer